Antecedentes y Objetivos: El endemismo es un fenómeno común de los organismos en las regiones áridas. En el presente trabajo se revisó la distribución de las plantas endémicas del Desierto Chihuahuense (DCH), cuya superficie abarca parte de los estados de Arizona, Chihuahua, Coahuila, Durango, Nuevo León, Nuevo México, San Luis Potosí, Tamaulipas, Texas y Zacatecas.Métodos: A través de la recopilación de información se elaboró una base de datos de especies con distribución restringida al DCH. Se consideraron los siguientes tipos de endemismo: 1) endémicos estrictos: aquellos elementos con localización conocida solo para el área de estudio, 2) cuasi-endémicos: aquellos presentes principalmente en el DCH y algunas poblaciones en localidades vecinas, 3) micro-endémicos: los que tienen una distribución restringida a una sola localidad y 4) endémicos a la región, pero de ecosistemas no áridos.Resultados clave: Se identificaron 826 taxa (incluye especies, taxa infraespecíficos adicionales e híbridos) que representan 24.87% de la flora total, 560 elementos de distribución endémica, 165 cuasi-endémicos, 176 micro-endémicos y 116 de ecosistemas no áridos. Las familias con mayor cantidad de endemismos son Cactaceae (141 especies), Asteraceae (106), Boraginaceae (34) y Brassicaceae (31) que en conjunto representan 46.2% del total. Los géneros con mayor número de taxa son Coryphantha (24), Echinocereus (14), Mammillaria (15) y Turbinicarpus (15), así como nueve géneros exclusivos al DCH. Las formas biológicas dominantes son las hierbas perennes y arbustivas, presentándose frecuentemente en el matorral xerófilo. La distribución endémica es de forma heterogénea, con una densidad de 0.128 especies/km2. Coahuila concentra la mayor proporción de elementos (31.15%).Conclusiones: Se sugiere continuar con la protección de Cuatro Ciénegas, Brewster, las Sierras La Madera y El Carmen y proponer como áreas de conservación a las Sierras de Parras, La Paila y Jimulco, y Concepción del Oro y Presidio, por presentar una alta concentración de endemismos.

Natural biostimulants, such as microorganisms and seaweed extracts, are used in agriculture to improve crop yields with a sustainable approach. However, the interaction effects between different biostimulants have not been thoroughly investigated. The objective of this work was to evaluate the synergistic effects of microorganisms (Glomus intraradices and Azospirillum brasilense) and seaweed extract (Ascophyllum nodosum and Macrocytis pyrifera) on growth, yield and fruit quality of cucumber plants under soilless cultivation. Two doses of microorganisms (0 and 10 spores mL-1 + 106 CFU) and four concentrations of seaweed extract (0, 250, 500 and 2500 ppm) were evaluated. The experimental design used was a randomized complete block design with a factorial arrangement (2 x 4), with four replications per treatment. The results showed that the equatorial diameter of the fruit, yield and titratable acidity improve when applying microorganisms and seaweed extract in combination; however, when applying the two biostimulants the values ​​of plant height, stem diameter, number of leaves, root length, biomass (fresh and dry), firmness, total soluble solids, vitamin C, chlorophyll (a and total) and indices of color (L* and b*) did not exceed those obtained when the biostimulants were applied individually. The combined application of microorganisms and seaweed extract improves cucumber yield, but not vegetative growth and, except for titratable acidity, fruit quality attributes.

This study concerned the anaerobic treatment of five different industrial wastewaters with a diverse and complex chemical composition. The kinetics of biotransformation of this wastewater at different chemical oxygen demand (COD) were studied in a batch reactor. Wastewater from an amino acid producing industry (Fermex) and from a tank that received several types of wastewaters (collector) contained 0.83 g l⁻¹ and 0.085 g l⁻¹ sulfate, respectively. During the study period of 20 days, methane formation was observed in all types of wastewaters. Studies on COD biodegradation showed the reaction velocity was higher for Fermex wastewater and lower for collector wastewater, with values of 0.0022 h⁻¹ and 0.0011 h⁻¹, respectively. A lower methanogenic activity of 0.163 g CH₄ day⁻¹ g⁻¹ volatile suspended solids (VSS) and 0.20 g CH₄ day⁻¹ g⁻¹ VSS, respectively, was observed for paper producing and brewery wastewater. Adapted granular sludge showed the best biodegradation of COD during the 20-day period. The sulfate-reducing activity in pharmaceutical and collector wastewater was studied. A positive effect of sulfate-reducing activity on methanogenic activity was noted for both types of wastewaters, both of which contained sulfate ions. All reactions of methane generation for the tested industrial wastewaters were first-order. The results of this study suggest that the tested wastewaters are amenable to anaerobic treatment.